/*
 * FXGL - JavaFX Game Library. The MIT License (MIT).
 * Copyright (c) AlmasB (almaslvl@gmail.com).
 * See LICENSE for details.
 */
package com.almasb.fxgl.physics.box2d.common;

import com.almasb.fxgl.core.math.Vec2;

import java.io.Serializable;

// updated to rev 100

/**
 * A transform contains translation and rotation. It is used to represent the position and
 * orientation of rigid frames.
 */
public class Transform implements Serializable {
    private static final long serialVersionUID = 1L;

    /** The translation caused by the transform */
    public final Vec2 p;

    /** A matrix representing a rotation */
    public final Rotation q;

    /** The default constructor. */
    public Transform() {
        p = new Vec2();
        q = new Rotation();
    }

    /** Initialize as a copy of another transform. */
    public Transform(final Transform xf) {
        p = xf.p.clone();
        q = xf.q.clone();
    }

    /** Initialize using a position vector and a rotation matrix. */
    public Transform(final Vec2 _position, final Rotation _R) {
        p = _position.clone();
        q = _R.clone();
    }

    /** Set this to equal another transform. */
    public final Transform set(final Transform xf) {
        p.set(xf.p);
        q.set(xf.q);
        return this;
    }

    /**
     * Set this based on the position and angle.
     *
     * @param p
     * @param angle
     */
    public final void set(Vec2 p, float angle) {
        this.p.set(p);
        q.set(angle);
    }

    /** Set this to the identity transform. */
    public final void setIdentity() {
        p.setZero();
        q.setIdentity();
    }

    public final static Vec2 mul(final Transform T, final Vec2 v) {
        return new Vec2(T.q.c * v.x - T.q.s * v.y + T.p.x, T.q.s * v.x + T.q.c * v.y + T.p.y);
    }

    public final static void mulToOut(final Transform T, final Vec2 v, final Vec2 out) {
        final float tempy = T.q.s * v.x + T.q.c * v.y + T.p.y;
        out.x = (T.q.c * v.x - T.q.s * v.y) + T.p.x;
        out.y = tempy;
    }

    public final static void mulToOutUnsafe(final Transform T, final Vec2 v, final Vec2 out) {
        assert v != out;
        out.x = T.q.c * v.x - T.q.s * v.y + T.p.x;
        out.y = T.q.s * v.x + T.q.c * v.y + T.p.y;
    }

    public final static Vec2 mulTrans(final Transform T, final Vec2 v) {
        final float px = v.x - T.p.x;
        final float py = v.y - T.p.y;
        return new Vec2(T.q.c * px + T.q.s * py, -T.q.s * px + T.q.c * py);
    }

    public final static void mulTransToOut(final Transform T, final Vec2 v, final Vec2 out) {
        final float px = v.x - T.p.x;
        final float py = v.y - T.p.y;
        final float tempy = -T.q.s * px + T.q.c * py;
        out.x = T.q.c * px + T.q.s * py;
        out.y = tempy;
    }

    public final static void mulTransToOutUnsafe(final Transform T, final Vec2 v, final Vec2 out) {
        assert v != out;
        final float px = v.x - T.p.x;
        final float py = v.y - T.p.y;
        out.x = T.q.c * px + T.q.s * py;
        out.y = -T.q.s * px + T.q.c * py;
    }

    public final static Transform mul(final Transform A, final Transform B) {
        Transform C = new Transform();
        Rotation.mulUnsafe(A.q, B.q, C.q);
        Rotation.mulToOutUnsafe(A.q, B.p, C.p);
        C.p.addLocal(A.p);
        return C;
    }

    public final static void mulToOut(final Transform A, final Transform B, final Transform out) {
        assert out != A;
        Rotation.mul(A.q, B.q, out.q);
        Rotation.mulToOut(A.q, B.p, out.p);
        out.p.addLocal(A.p);
    }

    public final static void mulToOutUnsafe(final Transform A, final Transform B, final Transform out) {
        assert out != B;
        assert out != A;
        Rotation.mulUnsafe(A.q, B.q, out.q);
        Rotation.mulToOutUnsafe(A.q, B.p, out.p);
        out.p.addLocal(A.p);
    }

    private static Vec2 pool = new Vec2();

    public final static Transform mulTrans(final Transform A, final Transform B) {
        Transform C = new Transform();
        Rotation.mulTransUnsafe(A.q, B.q, C.q);
        pool.set(B.p).subLocal(A.p);
        Rotation.mulTransUnsafe(A.q, pool, C.p);
        return C;
    }

    public final static void mulTransToOut(final Transform A, final Transform B, final Transform out) {
        assert out != A;
        Rotation.mulTrans(A.q, B.q, out.q);
        pool.set(B.p).subLocal(A.p);
        Rotation.mulTrans(A.q, pool, out.p);
    }

    public final static void mulTransToOutUnsafe(final Transform A, final Transform B,
                                                 final Transform out) {
        assert out != A;
        assert out != B;
        Rotation.mulTransUnsafe(A.q, B.q, out.q);
        pool.set(B.p).subLocal(A.p);
        Rotation.mulTransUnsafe(A.q, pool, out.p);
    }

    @Override
    public final String toString() {
        String s = "XForm:\n";
        s += "Position: " + p + "\n";
        s += "R: \n" + q + "\n";
        return s;
    }
}
